This application relates to a multi-station robotic welding assembly. The invention utilizes two or more industrial robots each including a welding torch at a distal end of a movable arm and wrist. Welding is carried out by moving the welding torch along a taught path relative to a workpiece. When a welding operation is started, a preset welding voltage and current are commanded from a robot control device to a controller of a welding machine. On receiving the command, the welding machine supplies electric power between the workpiece and an electrode of the welding torch. When an arc discharge is generated between the workpiece and the electrode, it is detected by the controller of the welding machine, which then supplies an arc generation signal to the robot control device. On receiving the arc generation signal, the robot control device commands welding voltage and current for normal welding to the controller of the welding machine, and at the same time, actuates the robot arm to move the welding torch along the taught path.
In a typical weld cell, a single industrial robot is used to weld all or part of a workpiece held in a fixture. The workpiece may include, for example, disassembled parts for bumpers, foot plates, headlight supports, arm rests, and other components commonly used in all-terrain vehicles (ATVs) and golf carts. The workpiece is first loaded into the fixture by an operator, who then waits as the welding process is completed. After welding, the assembled workpiece is removed from the fixture and generally powder coated before shipping to the customer. The cumulative operator “down time” during the welding process over a given shift is substantial, and results in a relatively inefficient process. The present invention addresses this problem. The invention further provides a multi-station robotic weld cell which can be quickly and conveniently relocated as a single unit without substantial disassembly or breaking down of parts.